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Joined: May 2014
Posts: 599
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But if it were 4578g it would be 4.578kg...so I don't see why if you first measured in grams to precisely 4500 that it wouldn't be 4.500 or 4.5 kg --to me both answers are okay but what do I know..
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Joined: Mar 2010
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4578 is clearly a precise amount down to its last digit (all the digits are "significant"), while 4500 may represented a rounded number. That's what Colinsmum means about guessing the level of precision when it's not stated.
But I think it's probably a safe bet that the teacher is not thinking about significant digits, and is just following an over-simplified rule.
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It is a little thing but according to ds7's teacher 4500g converts to 4.500kg. It is not inaccurate just incorrect and it makes me think she just taught them to move the decimal place rather than say there are 4.5 1000's in 4500. I'm just a 'umble maths prof, but that doesn't look incorrect to me, even if it is an opportunity to talk about precision and how to guess it when it isn't stated... Depends on whether that is a VALUE, or a MEASUREMENT. Since there are units attached, it is clearly the latter, and therefore significant figures should not be ignored. This kind of thing really comes back to bite kids in college science coursework. They simply cannot wrap their heads around significant zeros when they've had it drilled into them that nothing is ever just a placeholder. {sigh} This is why scientific notation rocks, by the way.
Schrödinger's cat walks into a bar. And doesn't.
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DS was doing an online problem set in math. He thought it would take him 90 minutes or so. After 2 or 3 hours, he was tearing his hair out and ready to give up altogether because he simply could not get the correct answer to a problem (you have to keep trying until you get it right in this system). He had tried everything he could think of, and still the system said it was wrong.
Turned out that his original answer was x.0. It should have been x.0000.
The system did NOT state something along the lines of, "Provide your answer to 4 decimal places."
I have heard many people complain that they or their kids spend n minutes solving a math/chem/physics/whatever problem and then 3n+ minutes trying to figure out how to format the answer so that the system likes it.
I really, really, do not like these online systems. I don't like the formatting requirements, I don't like "get ten-in-a-row-right-or-start-again," I don't like the way they give you a menu of topics to do, I don't like the fact that the problems are not of the breadth and depth needed to gain a decent understanding of a subject, and so on.
Last edited by Val; 02/10/15 10:40 AM. Reason: More detail added
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More bad homework: my two younger kids come home with packet work that includes giant word searches and "puzzlers" along the lines of "Vocabulary words from the chapter are hidden in the phone numbers below! Use the key on the keypad to figure out what word this is:
467-3287 (Hint: creepy!)
The answer to that one was "insects." My kids do not think insects are creepy, nor do I. I don't remember how long it took to decode those terms, but nothing was learned about insects or reptiles and whatever that third term was in the process. But I suppose that had I told them, my kids might have learned that people used to cause repetitive strain injuries in their thumbs by using keypads to send text messages. But alas, we were so annoyed when it was done, they just went to bed.
Teachers give out this stuff because it's "fun." IMO, a word search is fun on a rainy Saturday when you feel like doing a word search. It is not fun when it's Tuesday night after dinner and you have 4 other things to get done (including those stupid phone numbers, a study guide, and some essay questions), and it's going to take a half-hour to find a long list of vocabulary words embedded in a 15x15 matrix.
I told my kids that I'll be doing word searches and phone number puzzles from now on.
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Joined: Mar 2013
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More bad homework: my two younger kids come home with packet work that includes giant word searches and "puzzlers" along the lines of "Vocabulary words from the chapter are hidden in the phone numbers below! Use the key on the keypad to figure out what word this is:
467-3287 (Hint: creepy!)
The answer to that one was "insects." My kids do not think insects are creepy, nor do I. I don't remember how long it took to decode those terms, but nothing was learned about insects or reptiles and whatever that third term was in the process. But I suppose that had I told them, my kids might have learned that people used to cause repetitive strain injuries in their thumbs by using keypads to send text messages. But alas, we were so annoyed when it was done, they just went to bed.
Teachers give out this stuff because it's "fun." IMO, a word search is fun on a rainy Saturday when you feel like doing a word search. It is not fun when it's Tuesday night after dinner and you have 4 other things to get done (including those stupid phone numbers, a study guide, and some essay questions), and it's going to take a half-hour to find a long list of vocabulary words embedded in a 15x15 matrix.
I told my kids that I'll be doing word searches and phone number puzzles from now on. Yup..I've done word searches for my DS in elementary school. I completely agree they are not educational, are not fun for either DS or I and are an excellent example of busywork. I'm normally a parent that insist if my kid can't finish the homework to just turn it in that way, BUT I will do is do a word search for a kid because I don't see ANY educational value and they take my son forever. I would probably talk with to the teacher about this kind of homework and warn them that in the future you won't have your kids do this type of work.
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Joined: Feb 2014
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DD has real work for the first time in two years... which means I can participate in this thread now!
A recent math question for an online curriculum:
Explain how you would draw a model to show the solution to the equation 2x=6. State the solution and explain how the model helps you find the solution.
DDs answer:
"I am not a visual thinker. Models do not make sense to me, however I understand to solve the problem I need to isolate X. I understand that multiplication and division are inverse operations.
Thank you and sorry about the inconvenience."
She then went on to describe how she would solve the problem... and got the correct answer.
I can't wait to see what the teacher makes of this response.
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Joined: Sep 2013
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Oh Ivy -- I admire your DD! I hope the teacher takes it as politely as your daughter wrote her answer.
BTW, how is this solved using a model? Anything I come up with seems so messy and confusing!
Last edited by ConnectingDots; 02/10/15 12:49 PM.
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Joined: Feb 2011
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I'm interested in that outcome, too, Ivy. I told my kids that I'll be doing word searches and phone number puzzles from now on.I second the opinion re: online systems of "homework," by the way. And to be clear for everyone else-- this isn't in a primary or secondary setting, either-- but post-secondary. Truly appalling-- DD has reported that her faculty often have no idea just HOW bad they are to work with, unless students actually demonstrate how difficult it is to get the system to accept a correct solution.
Schrödinger's cat walks into a bar. And doesn't.
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Joined: Nov 2012
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I told my kids that I'll be doing word searches and phone number puzzles from now on. You're more sporting than me. I'd probably just attach a note to the unfinished page and say, "Incomplete with parent permission. If you have concerns, call me."
What is to give light must endure burning.
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